The proposed research is designed to study certain aspects of the biochemical and physiological processes that are fundamental to the maintenance of a normally functional cornea. In order that the tissue be transparent, a constant level of hydration must be maintained in the stroma, and this necessitates the continuous active extrusion of water across the endothelium. Accordingly, the metabolism of this cell layer will be investigated, with particular emphasis on the mechanisms by which anions may be transported from the stroma to the aqueous humor. The location of ion-dependent ATPases within the cell will be identified by means of differential and gradient centrifugation procedures. The role of glutathione in maintaining cellular integrity and pump function will also be investigated, in order to elucidate whether it has a specific extracellular or intracellular function.